What Features are most Important when Selecting an Inverter?
Inverters are the cornerstones of solar PV projects. They convert the direct current (DC) energy generated by solar panels into an alternating current (AC) that the local electrical grid or an alternative off-grid network can harness. Their importance to solar power generation is reflected in their cost: They are typically among the largest hardware-related expenses in solar implementations and can require substantial service and maintenance over time, similar to a car. Accordingly, it pays to make the right choice for the intended application.
There are multiple inverter options, including microinverters, or the string inverters and central inverters. For our purposes, we will focus predominantly on comparing the latter two in this post. Proper inverter selection should account for many criteria, the most important of which can usually be evaluated through the following questions:
1. How much size do I need?
The optimal inverter size will be determined by the applications that depend on it. Which brings us to…
2. What applications am I supporting?
String inverters are less powerful and more diminutive than central inverters, but these characteristics are advantageous in a lot of solar applications. For example, their light weight and overall flexibility and molecularity make them ideal for wall-mount and tilt-mount projects within smaller commercial environments. At the same time, like many solar features, they are vulnerable to shading and as such might not function optimally within deployments facing multiple directions, such as ones on gabled roofs.
3. What is the total cost of ownership for the inverter?
Estimating the full cost of an inverter selection can be somewhat complicated. Since they are much smaller, string inverters have lower upfront costs than central inverters and are generally perceived as highly economical pieces of equipment. However, they can actually be more expensive per DC watt than central inverters.